Sulfurized diels-alder adducts and lubricants containing the same



United States Patent 3,498,915 SULFURIZED DIELS-ALDER ADDUCTS AND LUBRICANTS CONTAINING THE SAME Lester E. Coleman, Willoughby Hills, Ohio, assignor to The Lubrizol Corporation, Wicklitfe, Ohio, a corporation of Ohio No Drawing. Continuation-impart of application Ser. No. 657,520, Aug. 1, 1967. This application Dec. 16, 1968, Ser. No. 784,172

Int. Cl. Cm 1/38; C07g 17/00 US. Cl. 252-475 10 Claims ABSTRACT OF THE DISCLOSURE This is a continuation-in-part of copending application Ser. No. 657,520 filed Aug. 1, 1967, which in turn is a continuation-in-part of application Ser. No. 602,600 filed Dec. 19, 1966, both now abandoned.

This application relates to novel sulfur-containing organic compounds, compositions containing them, methods for their use, and processes for the preparation thereof. In particular, the invention relates to sulfur-containing compounds characterized by the presence within their structures of at least one cycloaliphatic group, to lubricants, fuels, and other compositions containing these compounds, and to a method for imparting oxidation-corrosion resistance properties and extreme pressure capabilities to lubricants and the like.

Accordingly, it is a principal object of this invention to provide novel sulfur-containing organic compounds.

Another object is to provide novel sulfur-containing organic compounds useful as additives in lubricant compositions.

A further object is to provide lubricant compositions characterized by imparting corrosion and oxidation resistance to metals exposed thereto.

A still further object is to provide lubricant compositions capable of withstanding. extreme pressures while retaining their lubricating properties.

An additional object of the invention is to provide methods for imparting extreme pressure and oxidationcorrosion inhibiting properties to lubricants.

Still another object is to provide sulfur-containing compounds useful as additives which inhibit oxidation and corrosion of metals exposed to diesel oils, kerosene, fuel oils, and other hydrocarbon liquids.

These and other objects of this invention are accomplished by providing oil-soluble sulfur-containing organic compounds characterized by the presence within their 3,498,915 Patented Mar. 3, 1970 structure of at least one substituted cycloaliphatic group wherein at least one nuclear carbon of said group is attached via a divalent sulfur radical containing at least two sulfur atoms to another nuclear carbon of said substituted cycloaliphatic group or a nuclear carbon of a different cycloaliphatic group, at least one substituent on the substituted cycloaliphatic group being other than a saturated aliphatic hydrocarbon radical. These compounds are prepared by heating a reaction mixture comprising sulfur and at least one cycloaliphatic compound having at least one unsaturated carbon-to-carbon bond in the cycloaliphatic nuclei. The compounds and their methods of preparations are discussed more fully hereinafter.

STARTING MATERIALS The unsaturated cycloaliphatic reactants contemplated as starting materials for synthesizing the compounds of this lnvention can be represented by the following formula:

[ V R a (1) Hydrogen. (2) Hydrocarbyl.

(3) A heterocyclic radical including fused ring heterocyclic radicals and preferably those monocyclic heterocyclic radicals having from five to six atoms in the nucleus thereof, not more than three being hetero atoms selected from the class consisting of nitrogen, sulfur, and oxygen, the remainder being carbon.

(4) The radical [R [WR 'W-R where m is zero or one and m is zero or a positive whole number of up to about twenty and, preferably, not more than about ten, the Ws are independently oxygen, divalent sulfur or =NR R and R are hydrocarbylene of up to about thirty carbons, R and R are hydrogen, hydrocarbyl of up to about thirty carbons, acyl, and NR R wherein R and R are hydrogen, hydrocarbyl of up to about thirty carbons and acyl and together R and R (and when the terminal W is :NR then also R and R together with the nitrogen to which they are attached may represent a fiveor six-membered nitrogen-containing monocyclic heterocyclic radical of the type discussed Il -a /R N-N can be where represents the nitrogen-containing monocyclic heterocyclic radical. In addition to the hetero nitrogen, the radical can contain hetero oxygen, hetero sulfur, and/or additional hetero nitrogen but not more than three of the nuclear atoms should be hetero atoms, the remainder being carbon. Examples of such heterocyclic groups are l-pyrrolinyl, l-pyrazolidinyl, l-imidazolinyl, l-piperidyl, l-piperazinyl, (4 ethylpiperazinyl), 1 (4 hydroxyethylpiperazinyl), 4-morpholinyl, etc.

(5) The radical where W is the same as W hereinabove and R is hydrogen, halo, hydrocarbyl of one to thirty carbons, and the is as defined above.

(7) Acyl. (8 Cyano. (9) Nitro. ('10) Halo.

In addition to the monovalent groups enumerated above to which the Rs may individually correspond, one or more pairs of Rs can also represent divalent groups as follows:

(A) A pair of Rs, one from each of two non-adjacent nuclear carbons can represent (1) a carbon-to-carbon bond between these carbons or (2) a divalent aliphatic radical (e.g. alkylene, oxy, etc.), both valences not arising from the same atom in the group, thereby encompassing polycyclic (e.g., bicyclic, etc.) cycloaliphatic compounds.

(B) A pair of Rs on the same carbon can represent a divalent aliphatic group (e.g., alkylene), both valences of the group not arising from the same atom in the group, thereby encompassing spirocyclic cycloaliphatic compounds.

The term hydrocarbyl as used in the specification and claims is intended to encompass the monovalent radical of an aliphatic, cycloaliphatic, aromatic, arylaliphatic, aliphaticaryl, arylcycloaliphatic, cycloaliphaticalkylaryl, cycloaliphaticaryl, and cycloaliphaticalkyl hydrocarbon, and the like of up to about 30 carbons. Similarly, hydrocarbylene encompasses the divalent radicals derived from these corresponding monovalent hydrocarbon radicals while hydrocarbylidene is intended to encompass the corresponding divalent radicals where the valences are derived from the same carbon atoms within the hydrocarbon group.

It is to be understood that the terms hydrocarbyl, hydrocarbylene, and hydrocarbylidene, can encompass those 4 hydrocarbon groups which contain non-hydrocarbon substituents such as halo, nitro, lower alkoxy, lower alkyl mercapto, hydroxy, mercapto, amino, and the like so long as the hydrocarbon character of the groups is not destroyed. The presence or absence of such substituents on the hydrocarbon groups is not an essential or critical feature of the invention. Such modification of the hydrocarbon groups is well within the skill of the art and does not represent a departure from the concept of the claimed invention. Normally, if substituents are present, there will not be more than four such substituents per group and not more than one such substituent for every two to three carbon atoms in the hydrocarbon group.

Hydrocarbyl radicals are illustrated by:

(1) Alkyl of up to about thirty carbons: Methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl, heptyl, nonyl, decyl, tridecyl, octadecyl, tricosyl, octacosyl etc.

(2) Alkenyl of up to about thirty carbons: Ethenyl, allyl, l-butenyl, isobutenyl, Z-pentenyl, 3,4-dimethyl-2- hexenyl, l-octenyl, l-decenyl.

(3) Cycloalkyl of up to about thirty carbons: Cyclopentyl, cyclohexyl, cyclooctyl, alkylcycloalkyl such as 2,3- dibutylcyclohexyl, cycloalkylcycoakyl such as 3-cyclohexylcyclohexyl, etc. (preferably, the number of carbons in the nucleus of the cycloalkyl groups is five or six, any additional carbons in these groups being derived from hydrocarbon containing substituents attached thereto, the total number of carbons being up to about twenty.)

(4) Cycloalkenyl of up to about thirty carbons: Cyclopentenes, cyclohexenes, cycloheptenes, etc. corresponding to the above class of cycloalkyl groups but containing at least one ethylenic linkage in the nucleus thereof.

(5) Aryl of up to about thirty carbons: Phenyl, naphthyl, alkylaryl such a didecylphenyl and tolyl, 3-propylnaphthyl, alkenylaryl such as p-allyl-phenyl, cycloalkyl aryl such as 3-cyclohexylphenyl, etc.

It is clear that there are many obvious variations of these hydrocarbyl groups which are clearly equivalent and fall within the scope of the present invention. Thus, other representative hydrocarbyl groups are arylalkyl such as benzyl and phenethyl, alkylarylalkyl such as tolylpropyl, cycloalkylalkyl such as cyclohexylmethyl, and the like.

Substituted hydrocarbyls considered substantial equivalents of the above are l3-chloroethyl, 3-nitropropyl, p-ethoxyphenyl, 3-propoxycyclohexyl, 3-hydroxypropyl, 3-trifluoromethylphenyl, (fl-hydroxy-ethoxy)ethyl, 3-aminonaphthyl, etc.

Hydrocarbylene groups are exemplified by the corresponding divalent class of radicals, that is, divalent radicals which are analogous in composition and structure to those monovalent radicals used to illustrate hydrocarbyl groups. This would include alkylene of one to thirty carbons such as methylene, butylene-1,3, amylene, decylene, and the like; alkenylene such as ethenylene, l-decenylene; cycloalkylene such as cyclohexylene; arylene such as phenylene and the like. The preferred hydrocarbylene groups are the alkylene and alkenylene groups of up to thirty carbons, and preferably up to about twenty carbons.

Similarly, hydrocarbylidene groups can be illustrated by those divalent radicals corresponding to the monovalent radicals illustrating hydrocarbyl groups above where the valences arise from the same carbon in the groups; i.e., alkylidene such as CH CH CH=, (CH C:, cycloalkylidene, alkenylidene, arylalkenylidene, aralkylidene, etc.

Representative of the preferred five to six membered heterocyclic radicals contemplated by this invention as defined hereinabove are pyrrolyl, pyrrolidinyl, pyrrolinyl, chromanyl, pyranyl, isochromanyl, thienyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, piperidyl, piperazinyl, morpholinyl, thiomorpholinyl, and the like. Also included within this group of heterocyclic radicals are the corresponding substituted heterocyclic radicals contaming from one to three substituents selected from the class consisting of lower alkyl, lower alkoxy, halo, hydroxy, mercapto, lower alkylmercapto, nitro, amino, and lower alkyl amino.

Within the genus of radicals represented by the formula %R11;|:W-R2

a preferred subgroup is that wherein R and R are each alkylene or alkenylene of up to about ten carbons and R is hydrogen, acyl, lower alkyl, and lower alkenyl. When W is =N-R R is preferably hydrogen, acyl, lower alkenyl, or lower alkyl. A further preferred subgenus is that wherein R and R are alkylene, R is hydrogen, acyl, or lower alkyl, and when W is =RR R is hydrogen, acyl, or lower alkyl.

The adjective lower as employed in conjunction with a term representing a hydrocarbon-containing radical in the specification and claims is intended to limit the carbon content of the hydrocarbon radical to a maximum of seven carbons. Thus, lower alkyl includes methyl, ethyl, butyl, tertiary butyl, isoamyl, heptyl, etc.

Acyl groups encompassed by the term acyl as used' in the present invention are those acyl radicals formed by removal of an -OH or SH group from an organic I acid. The acyl radicals can be derived from organic phosphorus acids, organic thiophosphorus acids, organic sulfur acids, carboxylic acids, and thiocarboxylic acids.

The phosphorus and thiophosphorus acids include the triand pentavalent organic phosphorus acids of the formula RII II RIII II WI! Formula II (a) Formula II (b) and the like where R" is as defined above for the phosphorus and the thiophosphorus acids. Examples of these acids are alkylsulfinic acids, alkylsulfonic acids, cycloalkylsulfinic acids, cycloalkylsulfonic acids, arylsulfinic acids, arylsulfonic acids, and the like. Specific examples include ethane sulfinic acid, naphthalene sulfinic acids, benzene sulfonic acid, butane sulfinic acid, petrosulfonic acids, cyclohexyl sulfonic acid, etc.

The carboxylic and thiocarboxylic acids from which the acyl radicals are derived corresponding to the formula wherein W" and R are as defined in the above discussion of the phosphorus and thiophosphorus acids. Included within this class of acids are the alkanoic acids, particularly the lower alkanoic acids, the higher fatty acids, arylcarboxylic acids, cycloaliphatic carboxylic acids, and their corresponding thio analogs. Illustrative of these acids are formic acid, oxalic acid, acetic acid, butanoic acid, lauric acid, stearic acid, myristic acid,

oleic acid, palmitic acid, benzoic acid, cyclohexylcarboxylic acid, dithioacetic acid, thionacetic acid, thiolacetic acid, thionobenzoic acid, and the like.

A preferred group of starting materials from the over all standpoint of availability, economy, and the performance of the final products are the Diels-Alder adducts. These are a well-known, art-recognized class of compounds prepared by the diene synthesis or Diels-Adler reaction. A summary of the prior are relating to this class of compounds is found in the Russian monograph, Dienovyi Sintes, Izdatelstwo Akademii Nauk SSSR, 1963 by A. S. Onischenko. (Translated into the English language by L. Mandel as A. S. Onischenko, Diene Synthesis, N.Y., Daniel Davey and Co., Inc. 1964). To avoid useless repetition of what is well-known in the art, this monograph and reference cited therein are incorporated by reference into the present specification.

Basically, the diene synthesis (Iiels-Adler reaction) involves the reaction of a conjugated diene,

, with an ethylenically or acetylenically unsaturated compound, C=C or CEC-, these latter being known as dienophiles. The reaction can be represented as follows:

The products, A and B are commonly referred to as Diels- Alder adducts. It is these adducts which are used as starting materials for the preparation of the novel sulfurized Diels-Alder adducts of the invention.

Representative examples of these 1,3-dienes include aliphatic conjugated diolefins or dienes of the formula Formula III M1 M3 M3 M4 wherein M through M are the same as R in Formula I with the proviso that a pair of Ms on adjacent carbons do not form an additional double bond in the diene. Preferably not more than three of the M variables are other than hydrogen and at least one is hydrogen. Moreover, when M through M are other than hydrogen, they are preferably alkyl, halo, alkoxy, alkenyl, alkenyloxy, carboxy, cyano, amino, alkylamino, dialkylamino, phenyl and phenyl substituted by one to three substituents corresponding to these M variables. Normally the total carbon content of the diene will not exceed twenty. In the most preferred aspects of the invention, adducts are used Where M and M are both hydrogen and at least one of the remaining M variables is also hydrogen. Preferably, the carbon content of these M variables when other than hydrogen is seven or less. In this most preferred class, those dienes where M, M M and M are hydrogen, chloro, or lower alkyl are especially useful. Piperylene, isoprene, methylisoprene, chloroprene, and 1,3-butadiene are among the latter especially preferred dienes for use in preparing the Diels-Alder adducts. Other specific aliphatic conjugated dienes illustrative of those represented by Formula III are presented in Table I.

TABLE I.DIENES CHa(CH2) 3- tert-butyl CH3 (CH2) 5-- CH3 CH:CH20- CHaCHr p-chloropheny1 Oyclohexoxy- Tolyl p-fluorophenyl- 3,4-dimethoxyghenyl- 3, methylenedioxypheuyl- NoTr:.-Unless otherwise indicated, the various M variables in this table are hydrogen.

In addition to these linear Lil-conjugated dienes, cyclic dienes are also useful as reactants. Examples of these cyclic dienes are the cyclopentadienes, fulvenes, 1,3- cyclohexadienes, 1,3-cycloheptadienes, 1,3,5-cycloheptatrienes, cyclooctateraene, and 1,3,5-cyclononatrienes. Various substituted derivatives of these compounds enter into the diene synthesis. However, with the exception of the cyclopentadienes and the 1,3-cyclohexadienes, the availability of the remaining cyclic reactants at the present time makes them commercially unfeasible for preparing the compounds of the present invention.

The dienophiles suitable for reacting with the above dienes to form the adducts used as reactants can be represented by the formula Formula IV K K2 K1/ a wherein the K variables are the same as the R variables in Formula I above with the proviso that a pair of Ks may form an additional carbon-to-carbon bond, i.e., KCEC-K but do not necessarily do so.

A preferred class of dienophiles are those wherein at least one of the K variables is selected from the class of electron-accepting groups such as formyl, cyano, nitro, carboxy, carbohydrocarbyloxy, hydrocarbylcarbonyl, hydrocarbylsulfonyl, carbamyl, acylcarbamyl, N-acyl-N hydrocarbylcarbamyl, N-hydrocarbylcarbamyl, and N,N- dihydrocarbylcarbarnyl. Those K variables which are not electron-accepting groups are hydrogen, hydrocarbyl, or substituted-hydrocarbyl groups. Usually the hydrocarbyl and substituted hydrocarbyl groups will not containlmore than ten carbon atoms each.

The hydrocarbyl groups present as N-hydorcarbyl substituents are preferably alkyl of one to thirty carbons and especially one to ten carbons. Representative of this class of dienophiles are the following: nitroalkenes, e.g., 1- nitrobutene-l, l-nitropentene-l, 3-methyl-1-nitrobutene-1,

9 l-nitroheptene-l, l-nitrooactene-l, 4-ethoxy-l-nitrobutene- 1; alpha, beta-ethylenically unsaturated aliphatic carboxylic acid esters, e.g., alkylacrylates and ot-methyl alkylacrylates (i.e., alkyl methacrylates) such as butylacrylate and butylmethacrylate, decyl acrylate and decylmethacrylate, di-(n-b-utyD-maleate, di-(t-butylmaleate); acrylonitrile, methacrylonitrile, beta-nitrostyrene, methylvinylsulfone, acrolein, acrylic acid; alpha,beta-ethylenically unsaturated aliphatic carboxylic acid amides, e.g., acrylamide, N,N-dibutylacrylamide, methacrylamide, N-dodecylmethacrylamide, N-pentylcrotonamide; crotonaldehyde, crotonic acid, 6,5-dirnthyldivinylketone, methylvinylketone, N-vinyl pyrrolidone, alkenyl halides, and the like.

An especially preferred class of dienophiles are those wherein at least one K variable is where R is the residue of a saturated aliphatic alcohol of up to about forty carbon atoms; e.g., for example at least one K is carbohydrocarbyloxy such as carboethoxy, carbobutoxy, etc. the aliphatic alcohol from which R is derived can be a mono or polyhydric alcohol such as alkyleneglycols, alkanols, aminoalkanols, alkoXy-substituted alkanols, ethanol, ethoxy ethanol, propanol, B-diethylaminoethanol, dodecyl alcohol, diethylene' glycol, tripropylene glycol, tetrabutylene glycol, hexanol, octanol, isoocty alcohol, and the like. In this especially preferred class of dienophiles, not more than two K variables will be 0 ll o R.

groups and the remaining K variables will be hydrogen or lower alkyl, e.g., methyl, ethyl, propyl, isopropyl, and the like.

Examples of dienophiles of the type discussed above appear in Table II hereafter.

TABLE II.-DIENOPHILES HOOC- HOOC- 0 H 0 H3- S a-pyridyl B-Dy idy1 v-pyr y Oao-uitrop henylm-n1trophenyl-- p-nitrophenyl- N Og N 02- O [I ClS-- NOz CHaCHaCHr NOz- CH3(CH2)5 I CH3(CH2)30C -CH3 O [I H-C- phenyl- HO O C- naphthyl- II HOOC CHaC- I] ll omomo- CH3C- 0 II H-C- CH3 HOOC- CH3- ll C1CH3C- Phenyl- C1- ll ll Pheny1C phenyl-C- II 1] CH3CH20C CH CHz0C 1] ll CHgCHzO-C- CHaCHnO-C- H 1] CH CH0-C- CH;OHa0-C- CH II II OH3CH20C CHzCH20C- i-propyl- I I II CH30H20-C- CH3CH20-C- i-butyl- H II CH OH O-C CH3CHzO-C pheuyl- O l Cetyl-0C Cetyl-O- HOOO HOOC-CHP HOOC- CHz- HOOC- 0 ll Cl-C l i.e., maleic anhydride.

Norm-Unless otherwise indicated, the various K variables in this table are hydrogen.

In addition to the ethylenically unsaturated dienophilies, there are many useful acetylenically unsaturated dienophiles such as propiolaldehyde, methylethynylketone, propylethylnylketone, propenylethynylketone, propiolic acid, propiolic acid nitrile, ethylpropiolate, tetrolic acid, propargylaldehyde, acetylenedicarboxylic acid, the dimethyl ester of acetylene dicarboxylic acid, dibenzoy-lacetylene, and the like.

Cyclic dienophiles include cyclopentenedione, coumarin, 3-cyanocoumarin, dimethyl maleic anhydride, 3,6-endomethylene-cyclohexenedicarboxylic acid, etc. With the exception of the unsaturated dicarboxylic anhydrides derived from linear dicarboxylic acids (e.g., maleic anhydride, methylmaleic anhydride, chloromaleic anhydride), this class of cyclic dienophiles are limited in commercial usefulness due to their availability and other economic considerations.

The reaction products of these dienes and dienophiles correspond to the general formulae wherein M through M and K through K are as defined hereinbefore. If the dienophile moiety entering into the reaction is acetylenic rather than ethylenic, two of the K variables, one from each carbon, from another carbonto-carbon double bond. Where the diene and/or the dienophile is itself cyclic, the adduct obviously will be bicyclic, tricyclic, fused, etc., as exemplified below:

Reaction Normally, the adducts involve the reaction of equimolar amounts of diene and dienophile. However, if the dienophile has more than one ethylenic linkage, it is possible for additional diene to react if present in the reaction mixture.

PROCESS The sulfur-containing compounds of the present invention are readily prepared by heating a mixture of at least one of the substituted unsaturated cycloaliphatic compounds of the type discussed hereinabove and sulfur at a temperature within the range of from about 11*!) C. to just below the decomposition temperature of the Diels-Alder adducts. Temperatures within the range of about 110 to about 200 C. will normally be used. This reaction results in a mixture of products, some of which have been identified. In the compounds of known structure, the sulfur reacts with the substituted unsaturated cycloaliphatic reactants either at a double bond in the nucleus of the unsaturated reactant or at an allylic hydrogen and forms a divalent sulfur radical, containing at least two sulfur atoms, which joins two nuclear carbons of the same or difierent cycloaliphatic group.

The ratio of reactants can vary over a wide range, for example, a molar ratio of sulfur to unsaturated cycloaliphatic reactant of from about 0.5 :1.0 to 10011.0. As it is normally desirable to incorporate as much stable sulfur into the sulfur-containing compound as possible, a molar excess of sulfur is normally employed. Generally, the molar ratio of sulfur to unsaturated reactant will be about 1.0:1.0 to about 4.011.0 and preferably about 2.0:1.0 to about 41011.0 based on the presence of one ethylenically unsaturated bond in the cycloaliphatic nucleus. If there are additional unsaturated bonds in the cycloaliphatic nucleus, the ratio of sulfur may be increased.

The reaction can be conducted in the presence of suitable inert organic solvents such as mineral oils, alkanes of seven to eighteen carbons, etc., although no solvent is generally necessary. After completion of the reaction, the reaction mass can be filtered and/or subjected to other conventional purification techniques. There is no need to separate the various sulfur-containing products as they can be employed in the form of a reaction mixture comprising the compounds of known and unknown structure.

As hydrogen sulfide is an undesirable contaminent in lubricants, etc., it is advantageous to employ standard procedures for assisting in the removal of the H 8 from the products. Blowing with steam, alcohols, or nitrogen gas assists in the removal of H 5 as does heating at reduced pressures with or without the blowing.

PRODUCTS Formula VI wherein the R s are the same as R in Formula I with the exception that it is not necessary that at least one pair of R s on adjacent carbons form another carbon-to-carbon bond. If there is only one double bond in the cycloaliphatic ring and the sulfur reacts at this point, there would be no double bond remaining. On the other hand, if the sulfur reacts with an allylic hydrogen, the double bond need not be disturbed. Analysis of the productsshow that the sulfur reacts at both points producing both types of products. Y represents a divalent sulfur radical, L, L, L", and L' are integers of Zero to nine with the proviso that 4Lg+L' 9 and 35L"+L'58.

A preferred group of compounds are those wherein the total number of carbons in the rings is five or six, i.e., L+L= 4 or 5 and L"+L- =3 or 4. A particularly useful group of compounds are those wherein from one to five of the R s in each of the cycloaliphatic nuclei are other than hydrogen and at least one such substituent in each compound is other than saturated aliphatic hydrocarbyl.

When the unsaturated cycloaliphatic reactant is a Diels-Alder adduct, such as represented by Formula V(A) or (B), the sulfur-containing products of known structure correspond to the following generic formulae:

Formula IX wherein M and M are the same as M through M above and K and K are the same as K through K above. Y is a divalent sulfur radical. The variables q and q are zero or a positive whole number of one to six v and v are zero or positive whole number of one to four, at least one of M, M", K, and K in each compound being other than hydrogen or a saturated aliphatic hydrocarbon radical. Generally not more than five of the M and K variables on each ring are other than hydrogen. Preferably, at least one K variable in each compound will be an electron accepting group of the type discussed supra. The preferred class of substituents discussed hereinbefore with regard to the various K and M variables on the intermediates for making the Diels-Alder adducts and the adducts themselves obviously applies to the final products prepared from the intermediates.

An especially preferred class of sulfurized Diels-Alder adducts within the ambit of Fomrulae IX-XI is that whereinat least one of the K variables is an electron accepting group from the consisting of Formula X Formula XI wherein W and R are as defined above. Preferably, W is oxygen and R is hydrogen, halo, alkyl of one to thirty carbons, alkenyl of one to thirty carbons, hydroxy, alkoxy of one to thiry carbons, alkenoxy of one to thirty carbons, amino, alkylamino and dialkylamine wherein the alkyl groups contain from one to thirty carbons and preferably one to ten carbons. When R is halo, chloro is preferred. Particularly useful are those compounds wherein the Ms are hydrogen or lower alkyl and one K variable is carboalkoxy of up to thirty-one carbon atoms, the remaining K being hydrogen, lower alkyl, or another electron accepting group. Within this latter group, those wherein the carboalkoxy group is carbo-n-butoxy produce excellent results as lubricant additives.

The divalent sulfur radical Y-- is representative of a divalent sulfur group containing an average of from two to about ten sul'furs per divalent radical. Sulfur radicals containing from-two to six, sulfurs'are particularly useful. Illustrative of the radicals are the following: (S,) where r is a whole number of two to ten such s -%-s, s ss, etc. The sulfur generally is present in the linear polysulfide form, i.e., S,, where x is a whole number of two to ten and preferably two to six, e.g., -S-S,

In addition to these reaction products of known structure, there are additional sulfur-containing reaction products of unknown structure present within the reaction mass which are useful in the same manner as the products of known structure. While it has not been determined conclusively, it is believed that at least a part of the reaction products of unknown structure consist of three or more of the cycloaliphatic groups joined through divalent sulfur radicals. These products could be represented as (YA)b-Y A-Y-A-Y-A, A A

etc., wherein Y is a divalent sulfur radical, b is a positive whole number greater than one and the As represent cycloaliphatic groups of the types illustrated with regard to the compounds of known structure. Since part of the cycloaliphatic starting material can remain unreacted, it may also be a constituent in the reactiton products.

The products and products of this invention are further exemplified by the following examples.

Example 1 A mixture comprising 400 grams of toluene and 66.7 grams of aluminum chloride is charged to a two-liter flask fitted with a stirrer, nitrogen inlet tube, and a solid carbon dioxide-cooled reflux condenser. A second mixture comprising 640 grams (5 moles) of butylacrylate and 240.8 grams of toluene is added to the AlCl slurry while maintaining the temperature within the range of 37 to 58 C. over a 0.25 hour period. Thereafter, 313 grams (5.8 moles) of butadiene is added to the slurry over a 2.75 hour period while maintaining the temperature of the reactiton mass at 5061 C. by means of external cooling. The reaction mass is blown with nitrogen for about 0.33 hour and then transferred to a four-liter sepratory funnel and washed with a solution of 150 grams of concentrated hydrochloric acid in 1100 grams of water. Thereafter, the product is subjected to two additional water washings using 1000 ml. of water for each wash. The washed reaction product is subsequently distilled to remove unreacted butylacrylate and toluene. The residue of this first distillation step is subjected to further distillation at a pressure of 9-10 millimeters of mercury whereupon 785 grams of the desired product is collected over the temperature of -115 C.

Example 2 The adduct of isoprene and acrylonitrile is prepared by mixing 136 grams of isoprene, 106 grams of acrylonitrile, and 0.5 gram of hydroquinone (polymerization) inhibitor) in a rocking autoclave and thereafter heating for 16 hours at a temperature within the range of C. The autoclave is vented and the contents decanted thereby producing 240 grams of a light yellow liquid. This liquid is stripped at a temperature of 90 C. and a. pressure of 10 millimeters of mercury thereby yielding the desired liquid product as the residue.

Example 3 Using the procedure of Example 2, 136 grams of isoprene, 172 grams of methylacrylate, and .9 gram of hy droquinone are converted to the isoprene-methylacrylate adduct.

Example 4 Again following the procedure of Example 2, 104 grams of liquified butadiene, 166 grams of methylacrylate, and 1 gram of hydroquinone are charged to the rocking autoclave and heated to 130-135 C. for 14 hours. The product is subsequently decanted and stripped yielding 237 grams of the adduct.

Example 5 The adduct of isoprene and methyl methacrylate .is prepared by reacting 745 grams of isoprene with 1095 grams of methyl methacrylate in the presence of 5.4 grams of hydroquinone in the rocking autoclave following the precedure of Example 2 above. 1490 grams of the adduct is recovered.

Example 6 810 grams of the adduct of butadiene and dibutylmaleate are prepared by reacting 915 grams of dibutylmaleate, 216 grams of liquified butadiene, and 3.4 grams of hydroquinone in the rocking autoclave according to the technique of Example 2.

Example 7 A reacting mixture comprising 378 grams of butadiene, 778 grams of N-vinylpyrrolidone, and 3.5 grams of hydroquinone is added to a rocking autoclave previously chilled to 35 C. The autoclave is then heated to a temperature of 130l40 C. for about 15 hours. After venting, decanting, and stripping the reaction mass, 75 grams of the desired adduct are obtained.

Example 8 Following the technique of Example 2, 270 grams of liquified butadiene, 1060 grams of isodccylacrylate, and 4 grams of hydroquinone were reacted in the rocking autoclave at a temperature of 130-140 C. for about 11 hours. After decanting and stripping, 1136 grams of the adduct were recovered.

Example 9 Following the same general proceduce of Example 1, 132 grams (2 moles) of cyclopentadiene, 256 grams (2 moles) of butylacrylate, and 12.8 grams of aluminum chloride are reacted to produce the desired adduct. The butylacrylate and the aluminum chloride are first added to a two-liter flash fitted with stirrer and reflux condenser. While heating the reaction mass to a temperature within the range of 59 52 C., the cyclopentadiene is added to the flask over a 0.5 hour period. Thereafter the reaction mass is heated for about 7.5 hours at a temperature of 95 l00 C. The product is washed with a solution containing 400 milliliters of water and 100 milliliters of concentrated hydrochloric acid and the aqueous layer is discarded. Thereafter, 1500 grams of benzene are added to the reaction mass and the benzene solution is Washed with 300 milliliters of Water and the aqueous phase removed. The benzene is removed by distillation and the residue stripped at 0.2 millimeter of mercury to recover the adduct as a distillate.

Example 10 Following the technique of Example 2, the adduct of grams (1 mole) of decyl alcohol. The reactants are added to a. reaction flask and 3 grams of sodium methoxide are added. Thereafter, the reaction mixture is heated at a temperature of 190200 C. for a period of 7 hours. The reaction mass is washed with a 10% sodium hydroxide solution and then 250 milliliters of naphtha is added. The naphtha solution is washed with water. At the completion of the washing grams of toluene are added-and the reaction mass is stripped at 150 C. under pressure of 28 millimeters of mercury. 225 grams of a dark brown fluid product was recovered. This product is fractionated under reduced pressure resulting in the recovery of 178 grams of the product boiling in the range of 130133 C. at a pressure of 0.45 to 0.6 millimeter of mercury.

Following known Diels-Alder reaction techniques, for example that of Example 2 above, the adducts of the following dienes and dienophiles are prepared (1:1 mole adducts).

TABLE III Ex No. Diene Dienophile 12-.- Piperylene Acrolein.

3-CH -butenc-1.

. o 1-phenylbutadiene-1,3. Styrene.

20 Z-n'rethylbutadiene-l, 3. o-Nitrocinnamic acid. 21 2-phenylbutadiene-1, 3- Acrylamide. 22 2-methoxybutadiene-1, 3 Acrylid acie. 23 2-formyloxybutadiene-1, 3 p, fl-dimethyldivinylkctone. 24 2-tert-butylbutadiene-1. 3 Ethylmethacrylate. 25 Butadiene-l, 3. Vinylacetylene. 26- do Vinylacetate. 27 do Allyl alcohol. 28 do 2-nitro-butene-1 29 do- Methylvinyl sulione. 30 -do Vinyl sulfonyl chloride. 31 2, 3-dimethylbutadiene Vinyl acetate. 32- cyclopentadiene,-1, 3 Heptene-l. 33 -do Nitroethylene.

do Vinyl acetate. -do Diallyl ether. ..do p-Methoxyethylvinylketone. Cyclohexa ne-l, 3 Ethyl acrylate. -do Maleic anhydride. 1, 3-giphenylcyclohexadiene Do.

1, 40- Oycloheptadiene-l, 3 Acrolein. 41. 1, 5, S-trimethyl- Dirnethyl ester of acetylene cyclohexadiene-l, 3. dicarboxylic acid. 42- Butadiene-l, 3- N-(3-oxo-1, 1-dimethylbut yl)- acrylamide.

The following examples illustrate the preparation of the novel sulfur-containing compounds of the present invention.

Example I (a) To 255 grams (1.65 moles) of the isoprene-methacrylate adduct of Example 3 heated to a temperature of l10120 C., there are added 53 grams (1.65 moles) of sulfur flowers over a 45 minute period. The heating is continued for 4.5 hours at a temperature in the range of 130160 C. After cooling to room temperature, the reaction mixture is filtered through a medium sintered glass funnel. The filtrate consists of 301 grams of the desired sulfur-containing products.

'(b) In part (a) the ratio of sulfur to adduct is 1: 1. In this example, the ratio is 5:1. Thus, 640 grams (20 moles) of sulfur flowers is heated in a three-liter flask at C. for about 0.3 hour. Thereafter, 600 grams (4 moles)v of the isoprene-methacrylate adduct of Example 3 is added dropwise to the molten sulfur while maintaining the temperature at 174l98 C. Upon cooling toroom temperature, the reaction mass is filtered as above, the filtrate being the desired product.

(c) Seven hundred and fifty grams (5 moles) of the adduct employed in (a) and (b) above is heated to 105 C. under reflux conditions. To the heated adduct is added 320 grams (10 moles) of sulfur flowers in five increments over a 0.75 hour period while maintaining the temperature of the reaction mass at l05l12 C. The reaction mixture is heated for 6 hours at l50155 C. while bubbling nitrogen through the reaction mass at a rate Example II (a) A reaction mixture comprising 1175 grams (6 moles) of the Diels-Alder adduct of butylacrylate and isoprene and 384 grams (12 moles) of sulfur flowers is heated for 0.5 hour at l.08110 C. and then to 155-165 for 6 hours while bubbling nitrogen gas through the reaction mixture at 0.25 to 0.5 standard cubic feet per hour. At the end of the heating period, the reaction mixture is allowed to cool and'filtered at room temperature. Thereafter, the product is permitted to stand for 24 hours and refiltered. The filtrate weighing 1278 grams is the desired product.

(b) Following the procedure of Example II(a), 1275 grams (6.5 moles) of the adduct and 208 grams (6.5 moles) of sulfur flowers are reacted to produce 1421 grams of the desired sulfur-containing reaction prodnets.

Again, following the technique of (a), 2450 grams (12.5 moles) of the adduct of isoprene and butylacrylate is reacted with 600 grams of sulfur (18.75 moles) to produce 2814 grams of the desired sulfurcontaining products.

Example III (a) Sulfur (4.5 moles) and the adduct of isoprenemethyl-methacrylate (4.5 moles) are mixed at room temperature and heated for 1 hour at 110 C. while blowing nitrogen through the reaction mass 'at 0.25-0.5 standard cubic feet per hour. Subsequently the reaction mixture is raised to a temperature of 150155 C. for 6 hours while maintaining the nitrogen blowing. After heating, the reaction mass is permitted to stand for several hours while cooling to room temperature and is thereafter filtered. The filtrate consists of 842 grams of the reaction mixture of the desired sulfurcontaining product.

(b) Employing the technique of (a), 7.96 moles of sulfur flowers are reacted with 3.98 moles of the iso- .prene-methyl-methacrylate adduct to product 857 grams of the product.

' Example IV (a) Seven hundred grams (5.04 moles) of the adduct of butadiene and methylacrylate are mixed with 323 grams (10.08 moles) of sulfur flowers in the presence of 3% by weight based on the adduct of hydroquinone. The reactants are heated under reflux conditions while bubbling nitrogen through the reaction mass. Heating is gradual at first (room temperature to 110 C. during the first hour and from 110C. to 140 C. during the second hour). Thereafter, the reaction mixture is heated for 6 hours at a temperature within the range of 150- 160 C., permitted to cool to room temperature, and filtered twice. The filtrate consists of 930 grams of the desired sulfur-containing products.

(b) The same process as employed in (a) is repeated employing as the adduct a distilled butadiene-methylacrylate adduct which boils over the range of. 7l78 C. under a pressure of 18-19 millimeters of mercury. The reactants, 550 grams of the adduct (4.0 moles) and 256 grams of sulfur flowers (8.0 moles) are placed in a flask fitted with reflux condenser and a nitrogen gas inlet. The mixture is heated under reflux conditions for about 8% hours at a temperature within the range of 150160 C. while bubbling nitrogen gas through the mass at a rate of about 0.5 standard cubic feet per hour. Upon cooling to room temperature, the product is filtered yielding 810 grams of the desired product as the filtrate.

Example V A one-liter flask fitted with a stirrer, reflux, condenser, and nitrogen inlet line is charged with 256 grams (1 mole) of the adduct of butadiene and isodecylacrylate and, 64 grams (2 moles) of sulfur flowers and then heated for 12 hours at a temperature, stand for 21 hours, and filtered at room temperature to produce 286 grams of the desired product as the filtrate.

Example VI (a) A mixture comprising 420 grams (1.5 moles) of the adduct of isoprene and decylacrylate and 96 grams of sulfur flowers (3.0 moles) are reacted as in Example V producing 466 grams of the desired products.

(b) Employing the same reactants as in (a) above, the process conditions are modified and the ratio of sulfur to adduct increased from 2:1 to 7:1. A two-liter flask is charged with 224 grams of sulfur flowers (7.0 moles) and heated to C. to convert the sulfur to the molten state. Thereafter, 280 grams of the adduct is added in increments while raising the temperature of the reaction mass to 200 C. The reaction mass is heated for 11% hours at a temperature of 200244 C. Upon cooling, there was recovered 366 grams of a dark red viscous liquid which comprises the desired reaction products.

Example VII (a) 4550 grams (25 moles) of the adduct of butadiene-butylacrylate and 1600 grams (50 moles) of sulfur flowers are charged to a 12 liter flask, fitted with stirrer, reflux condenser, and nitrogen inlet tube. The reaction mixture is heated at a temperature Within the range of 155 C. for 7 hours while passing nitrogen therethrough at a rate of about 0.5 cubic feet per hour. After heating, the mass is permitted to cool to room temperature and filtered, the sulfur-containing products being the filtrate.

It has been found that, if the sulfur-containing prodnets of this invention are treated with an aqueous solution of sodium sulfide, containing from about 5% to about 75% by weight Na S, the treated product has much less tendency to darken freshly polished copper metal brought in contact with the product. In the socalled Copper Strip Test, the product of VII(a) gives a copper stn'p rating of 4c (copper is darkened to the point of being almost black). However, when 1000 grams of the product obtained before filtering is mixed with 1000 grams of an 18% solution of sodium sulfide (Na S) the rating was improved to within the range of 1a to 1b (almost no darkening of the copper).

Treatment involves the mixing together of the sulfurized reaction product and the sodium sulfide solution for a period of time suflicient for unreacted sulfur to be scavenged, usually a period of a few minutes to several hours depending on the amount of unreacted sulfur, the quantity and the concentration of the sodium sulfide solution. The temperature is not critical but normally will be in the range of about 20 C. to about 100 C. After the treatment, the resulting aqueous phase is separated from the organic phase by conventional techniques, i.e., decantation, etc. Other alkali metal sulfides, M 5 where M is an alkali metal and x is 1, 2, or 3 may be used to scavenge unreacted sulfur but those where x is greater than 1 are not nearly as effective. Sodium sulfide solutions are preferred for reasons of economy and effectiveness.

One thousand grams of the product of VH(a) obtained before filtering are heated to 100 C. in a three-liter flask fitted with a reflux condenser and stirrer. While stirring the adduct under at high speed, 1000 grams of the sodium sulfide solution are added over a one-minute period, cooling the mass to 38 C. The resulting mixture is again heated to 50 C. and held within the range of 42-50 C. for one hour using an infrared lamp. Upon standing, the reaction mixture separates into an aqueous phase and an organic phase. The lower or aqueous phase is removed. A 440 gram portion of the organic layer is filtered giving a filtrate weighing 401 grams which is the desired 19 product. The remaining portion of the organic layer is Washed in 500 grams of water at 40 C. for minutes and thereafter allowed to separate. The organic layer weighing 358 grams is stripped to remove the water. The product after water removal weighed 322 grams. The product obtained by the direct filtration of the sodium sulfide treated sulfur-containing adduct and the product obtained by first washing the sodium sulfide treated adduct were the same, both being substantially free from sodium.

(b) Following the procedure of VII(a), 1092 grams (6 moles) of the adduct of butadiene and butylacrylate and 192 grams (6 moles) of sulfur flowers are heated for 7 hours at aternperature of 150-155 C. After cooling the filtering, 1217 grams of a clear, yellow liquid filtrate is obtained as the product.

Example VIII The adduct of butadiene-butylacrylate was prepared by charging 513 grams (4 moles) of butadiene-1,3 to a twoliter flask fitting with a stirrer, reflux condenser, and nitrogen inlet tube. To the butadiene is added 50.4 grams of aluminum chloride (AlCl over a one-minute period while stirring the reaction mixture at a temperature Within the range of 25 28 C. A colorless clear solution resulted. The butadiene was blown into the aluminum chloride-butylacrylate mixture over a 1.75 hour period while maintaining the reaction mass at a temperature of 28-59 C.- Then the reaction mass is stirred for two hours while maintaining the temperature within the range of 41-52 C. followed by the addition of a solution of 150 milliliters of concentrated hydrochloric acid and 1000 grams of water to the reaction mass to hydrolyze the aluminum chloride. The resulting aqueous phase of the reaction mass is discarded. The organic phase is washed with 1000 milliliters of Water at 40 C. and the resulting aqueous phase is discarded leaving the organic phase as the desired adduct weighing 735 grams.

Two hundred grams of this product (1.1 moles) and 70.5 grams of sulfur flowers (2.2 moles) are mixed in oneliter flask fitted with a stirrer, reflux condenser, and nitrogen inlet tube. The mixture is heated to about 150 C. over a one-hour period and thereafter is maintained at a tempera-ture of l50-160 C. for 7 hours. During the reaction, nitrogen gas is blown through the reaction mass at a rate of about 0.25 standard cubic feet per hour. The resulting light orange colored liquid weighing 260 grams is then charged to a three-liter flask fitted with a stirrer and reflux condenser. A mixture of 173 grams of toluene and 260 grams of a 6% sodium sulfide solution in water are then added to the reaction mass and stirred at high speed for one hour at room temperature. After separating into two phases, there is obtained a 405 gram organic phase which is light yellow in color. This organic layer is stripped at reduced pressure to remove water and toluene. The residue weighing 235 grams is a light yellow oil which is filtered to produce 210 grams of the desired purified product as the filtrate.

Example IX Example X A reaction mixture comprising 782 grams (4.3 moles) of the Diels-Alder adduct of butadiene and butylacrylate and 138 grams (4.3 moles) of sulfur flowers is gradually heated from room temperature to 150 C. over a one-hour period and thereafter maintained at a temperature of 150 160 C. for 6 hours. The reaction product is then per- 20- mitted to cool to room temperature and stand for about 12 hours. The product is filtered providing 869 grams of filtrate representing the desired sulfur-containing reaction products.

Examples 'XI through XXIII illustrate the preparation of other sulfur-containing compounds of the present invention. In each case, the adduct and the sulfur were mixed in a reaction flask and thereafter heated to a temperature within the range of 160 C. for a period of 7 to 10 hours while bubbling nitrogen through the reaction mixture. The sulfurized products are then permitted to cool to room temperature and allowed to stand for several hours. Thereafter the reaction mass is filtered, the filtrate representing the desired sulfur-containing products.

Similarly other Diels-Alder adducts of the type disclosed above can be sulfurized in the manner illustrated by the foregoing examples to prepare other sulfurized Diels-Alder adducts of the type contemplated by the present invention.

It has also been determined that treatment of the reaction mass with solid, insoluble acidic materials such as acidified class or acidic resins and thereafter filtering the sulfurized reaction mass improves the product with respect to its color and solubility characteristics. Such treatment comprises thoroughly mixing the reaction mixture with from about 0.1% to about 10% by weight of the solid acidic material at a temperature of about 25 C. 150 C. and subsequently filtering the mass.

As previously mentioned, there is no need to separate the sulfur-containing products which are, produced in the above reactions. The reaction product is a mixture .which comprises the compounds whose structures have been ascertainedbut which also comprises compounds whose structures ,are unknown. Since it is economically unfeasible to separate the components of the reaction mixture, they are employed in combination as a mixture of sulfur-containing compounds.

In order to remove the last traces of impurities from the reaction mixture, particularly when the adduct employed was prepared using a Lewis acid catalyst (e.g., AlCl it is sometimes desirable to add an organic inert solvent to the liquidreaction product and, after thorough mixing, to refilter the material. Subsequently the solvent is stripped from the product. Suitable solvents include solvents of the type mentioned hereinabove such as benzene, toluene, the-higher alkanes, etc. A particularly useful class of solvents are the textile spirits.

In addition, other conventional purification techniques can .be advantageously employed in purifying products of I this invention. .For example, commercial filter aids can .be added to the materials prior to filtration to increase the efliciency ofthev filtration. Filtering through diatomaceous earth is particularly useful where the use contemplated requires the removal of substantially all solid materials. However, such expedients are well. known to those skilled in the art and require no elaborate di cussion herein.

21 Lubricant compositions The sulfur-containing products of the present invention will normally be employed'in an amount of from about 0.001% to about 20% by weight of the particular hydrocarbon liquid in which they are utilized. The compounds can be utilized in mineral lubricating oil compositions, synthetic lubricating oil compositions, cutting oils, gasolines, fuel oils, diesel fuels, etc. The optimum amount to be used in a given composition obviously would depend on the contents of the particular lubricating composition, the operating conditions to which it is to be subjected, and the particular additives employed. Thus, when employed as an axidation-corrosion inhibitor in lubricating oils for internal combustion engines, the sulfur-containing compositions of the invention will normally be employed in an amount of from about 0.05% to about by weight. However, when employed as an extreme pressure additive, such as in gear lubricants, the sulfur-containing compounds will be employed in amounts of from about 1% up to about by weight or even higher.

It is also contemplated that the lubricating compositions can encompass additives in addition to the sulfurcontaining compounds described herein. Illustrative of such additives are detergents of the ash-producing or the ashless type, pour point depressants, viscosity index improvers, anti-foam agents, rust inhibitors, other extreme pressure agents, additional oxidation and corrosion inhibiting agents, and the like. These additional constituents will be present in the lubricating compositions, if required, in amounts of about 0.001% to about 10% by Weight.

The ash-containing detergents include the oil-soluble neutral and basic salts of alkaline earth or alkali metals with sulfonic acids, carboxylic acids, or organic phosphorus acids having at least one direct carbon-to-phosphorus linkage such as those prepared by the treatment of an olefin polymer (e.g., polyisobutene having a molecular weight of about 1000) with a phosphorizing agent, e.g., phosphorus trichloride, phosphorus heptasulfide, phosphorus pentasulfide, etc. The most commonly used salts of these acids are those of sodium, potassium, lithium, calcium, magnesium, and barium. The basic salts are those acid salts wherein the metal is present in stoichiometrically larger amounts than in the normal neutral organic acid salts. These overbased salts are well known in the art and have been used extensively in the lubricant field.

Ashless detergents contemplated as additives in the compositions of the invention are illustrated by those disclosed in U.S. Patents 3,172,892; 3,219,666; etc.

Other extreme pressure agents and oxidation-corrosion inhibiting agents are exemplified by chlorinated aliphatic hydrocarbons such as chlorinated wax; organic sulfides and polysulfides such as benzylsulfide, bis-(chlorobenzyl) disulfide, dibutyltetrasulfide, phosphosulfurized hydrocarbons such as the reaction product of a phosphorus sulfide with turpentine or methyloleate; phosphorus esters including principally dihydrocarbon and trihydrocarbon phosphites such as dibutylphosphite, diheptylphosphite, dicyclohexylphosphite, pentylphenylphosphite,distearylphosphite, dimethylnaphthylphosphite, polypropylene (molecular weight of about 500) -substituted phenylphosphite, dipentylphenylphosphite, tridecylphosphite, diisobutyl-substituted phenylphosphite; metal thiocarbamates such as zinc dioctyldithiocarbamate, bariumheptylphenyldithiocarbamate; Group II metal phosphorodithioates such as zinc dicyclohexylphosphorodithioate, zinc dioctylphosphorodithioate, barium di(heptylphenyl)phosphorodithioate, cadmium dinonylphosphorodithioate, and the metal salt (e.g., zinc, lead, calcium, etc.) of a phosphorodithioic acid produced by the reaction of a phosphorus pentasulfide with an equimolar mixture of isopropanol and n-hexyl alcohol, or an equivalent amount of other alkanols or cycloalkanols such as disclosed in 2,820,723 and 2,861,907. The zinc salts are preferred.

Another class of useful additives which can advantageously be incorporated into the compositions of the present invention is the so-called hindered phenols, that is, phenolic compounds characterized by substituents in both positions ortho to the phenolic hydroxyl group. Examples of such phenols include 2,6-dialkylpheno1s and 2,4,6-trialkylphenols such as 2,6-di-(tert-butyl)-4-methylphenol, 2,6-di-(tert-butyl)-phenol, and 2,4,6-tri-(tertbutyl)-phenol. The alkyl groups will contain from one to eight carbons and preferably Will be branched, especially on the alpha carbon. Other hindered phenols include 2,6- dimethyl 4-cyclohexylphenol; 2,6-dicyclohexyl-4-methylphenol, etc. Also useful are hindered bisphenols such as 1,l-bis-(3,S-dialkyl-4-hydroxyphenyl) methanes in which all the alkyl groups contain from 1 to 8 and preferably from about 3 to 8 carbons. Again, alkyl groups which are branched on their respective alpha carbon atoms are particularly useful. Examples of these bisphenols include 1,1 bis-[3,5-di-(tert-butyl)-4-hydroxy-phenyl]methane, 1, l-bis- [3 ,5 -di (2-octyl) -4-hydroxy-phenyl] -methanes, and the like.

A particularly useful combination are those wherein at least one tri-hydrocarbyl-phosphite and at least one hindered phenol are used in combination with the sulfurcontaining compounds of the present invention as additives for lubricating oils. This combination can be employed with additional additives as set forth above. Generally the lubricant will contain from about 0.01% to 10% by weight and, preferably, from about 0.055% to about 5.0% of each of these three constituents. The term hydrocarbyl is intended to include any monovalent hydrocarbon radical. Examples of such phosphites include trialkylphosphites such as tridecylphosphite; triarylphosphites such as triphenylphosphite; triaryl phosphites wherein the aryl groups include one or more substituents particularly alkyl substituents; dialkylarylphosphites such as dipentylphenylphosphite and dimethylnaphthylphosphite; alkyldiarylphosphites such as decyldiphenyl phosphites, etc.

The following are illustrative examples of lubricant compositions containing the sulfur-containing compounds of the present invention. All percentages refer to percent by weight of total composition.

Example A SAE 10W-30 mineral lubricating oil containing 1% of the product of Example I(a).

Example B SAE 30 mineral lubricating oil containing 5% of the product of Example III(b), 0.075% of phosphorus as zinc di-n-octylphosphorodithioate, and 5% of the barium salt of an acidic composition prepared by the reaction of 1000 parts of a polyisobutylene having a molecular weight of about 60,000 with parts of phosphorus pentasulfide at 200 C. and hydrolyzing the product with steam at C.

Example D SAE l0W-30 mineral lubrication oil containing 4% of the product of Example V, 2% of the product obtained from reacting at 150 -165 C. for four hours while blowing With nitrogen 1000 parts by weight of polyisobutenesubstituted succinic anhydride (average mol Wt. of polyisobutylene substituent: 750) 70 parts of a commercially available ethylene polyamine mixture having an average 23 composition of tetraethylene pentamine in 500 parts of mineral oil; and of sulfate ash as barium mahogany sulfonate.

Example E SAE 20 mineral lubricating oil containing 0.4% of the Nags-treated product of Example VII(a), 0.2% of 2,4,6- tri-(tert-butyl)-pheno1 and 0.4% by weight of tri-tolylphosphite.

The corrosion-oxidation inhibiting qualities of the sulfur-containing compounds of the present invention is illustrated by engine test of lubricants containing these compounds. In a standard test for the industry, a lubricant containing the particular additive to be tested is placed in an engine and then the engine is operated for forty hours. At the end of the forty-hour period, the bearings are weighed to determine the loss of metal during engine operation. An additive is considered to be an effective corrosion-oxidation inhibitor in this particular test if the weight loss is 50 milligrams or less. Thus, when the product of Example He) is employed in a lubricating oil composition at a concentration of 0.4% by volume, the bearings undergo a 29.5 milligram weight loss; a similar concentration of the product of Example VII(a)'is characterized by 18.3 milligram weight loss, while the same concentration of the product of Example VIII limits th bearing weight loss to 16.6 milligrams.

Similarly, other of the novel sulfur-containing products tested at concentrations as low as 1% or less resulted in bearing Weight losses ranging from 19.0 milligrams to 45.3 milligrams. It is obvious that the results achieved with any given sulfur-containing compound will vary as the overall composition of the oil is varied. For example certain additives used in the lubricating art tend to promote corrosion. In the presence of such additives, it is obvious that more of the sulfur-containing compounds of the invention may be necessary to maintain comparable low-level bearing weight losses.

The ability of the sulfur-containing compounds to impart extreme pressure properties to lubricants is readily illustrated by the Timken OK Load Test. For example, an SAE 90 mineral oil composition containing 1% by Weight of the product of Example VIII produced a test result of 45 lbs.; at 1.5% the result was 55 lbs. However, in the absence of the sulfur-containing compound of the invention, the test result was lbs.

While the novel sulfur-containing compound of the present invention are primarily intended to be used as additives in hydrocarbon fuels and lubricating compositions, they also have properties which make them useful as accelerators in rubber treating processes, as pesticides such as insecticides and fungicides, as plasticizers, as asphalt additives, as ore-floatation agents and the like. The manner for employing the present compounds in these additional fields of use will be apparent to those skilled in the art.

What is claimed is:

1. A lubricating composition comprising a major amount of an oil of lubricating viscosity and an amount of at least one oil-soluble sulfur-containing material sufficient to impart extreme pressure properties to said composition, the oil-soluble sulfur-containing material being produced by reacting sulfur with at least one Diels-Alder adduct, the molar ratio of sulfur to adduct being from about 1:1 to about 4:1 wherein the adduct consists essentially of the 1:1 adduct of at least one dienophile selected from the group consisting of a,fi-ethylenically unsaturated aliphatic carboxylic acid esters, a,fi-ethylenically unsaturated aliphatic carboxylic acid amides, and a,B-ethylenically unsaturated aliphatic halides with at least one aliphatic conjugated diene corresponding to the formula 24 where M through M are each independently selected from the group consisting of alkyl, halo, alkoxy, alkenyl, alkenyloxy, carboxy, cyano, amino, alkylamino, dialkylamino, phenyl, and phenyl substituted with one to three ubstituents corresponding-to M through M 2. A lubricating composition according to claim 1 wherein the molar ratio of sulfur to adduct is about 2:1 to about 4: 1.

' 3. A lubricating composition according to claim 2 wherein the diene is further characterized in that M and M are hydrogen and M, M M and M are each independently hydrogen, chloro, or lower alkyl.

4. A lubricating composition according to claim 3 v wherein the dienophile is further characterized in that it contains at least one but not more than two the alkyl group.

8. A lubricating composltion according to claim 7 wherein the diene is 1,3-butadiene.

9. A lubricating composition according to claim 1 comprising avmajor amount of a mineral lubricating oil of lubricating viscosity and an amount of at least one oilsoluble sulfur-containing material sufficient to impart extreme pressure properties to said composition, the oilsoluble sulfur-containing material being produced by reacting sulfur with at least one Diels-Alder adduct at a temperature of about C. to about 200 C., the molar ratio of sulfur to adduct being from about 2:1 to about 4:1 wherein the adduct consists essentially of the 1: 1 mole adduct of at least one dienophile selected from the group consisting of a,B-ethylenically unsaturated aliphatic carboxylic acid esters with at least one'dienophile where M and M areeach hydrogen and M, M M and M are each independently hydrogen, chloro, or lower alkyl.

10. A lubricating composition according to claim 9 wherein the a,;3-ethylenically unsaturated carboxylic acid esters are alkyl esters of acrylic acid or methacrylic acid where the carboalkoxy groups contain up to thirty-one carbon atoms.

9 References Cited UNIIEDYSTVATES PATENTS 7/1942 Knowles et' al. 25248.6 X 2,325,040 7/1913 Cook 'et a1. 25248.6 2,424,588 7/1947 Sparks etal 25256 2,480,666 8/1949 Morway et'al. 252486 X 2,513,060 6/1950 Smith et'al. 252'48.6 2,969,326 l/ 1961 Dorinson et al. 260- X 2,993,856 .7/1961 'Heisig et al. 25248.6X

3,136,748 Miller et al. 25248.6 x

W YM AN, Primary Examiner CANNON, Assistant Examiner Y 7 Us. 01. m.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,498 ,915 March 3 1970 Lester E. Coleman It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below: I

Column 24, line 2, before "'alkyl" insert hydrogen Signed and sealed! this 27th day of October 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, J R.

Edward M. Fletcher, Ir.

Commissioner of Patents Attesting Officer 

